Two major standards were published in 2013 highlighting the requirements for competent bolting for those concerned with the management and assembly of bolted joints.
Joint integrity is the cornerstone of safe and leak-free operation in a pressurised system. Correct assembly is one of the primary factors integral to the integrity of a bolted joint. However, until 2013, bolting technicians were not held to the same competence standards as welders though their work objectives were directly comparable. For example, when comparing bolted and welded joints in the oil and gas industry, standards are very different. Similar disparities exist in other major industries, including mining and energy, infrastructure and process engineering, where pressurised joints are involved.
When dealing with welded joints, engineers need to ensure that they have strong material control, documented and approved procedures, and formally coded welders to perform the task. In addition welds are tested using non-destructive techniques and verified through hydro and/or gas-testing methods, all of it supported through fully documented traceability. These mandatory standards for welded joints have not typically been applied to bolted connections.
New standards for bolting
The American Society of Mechanical Engineers (ASME) updated the 2010 PCC-1 ‘Guidelines for Pressure Boundary Bolted Flange Joint Assembly’, which now includes an appendix defining the requirements for training and qualification of engineers working in the field of bolted joints.
The European Committee for Standardisation (CEN) re-published EN1591 Part 4 with modifications. This is now referred to as ‘Flanges and their Joints - Part 4: Qualification of personnel competency in assembly of the bolted connections of critical service pressurised systems’.
Through the publications of these standards, industry has been provided guidance in the assembly and assurance of bolted connections similar to the control and assurance of the welded joint. Field personnel will now have to prove their competency every three years, document their activities using pre-approved procedures and traceable bolt loads, and maintain a permanent record for future reference. By rigorously following these standards, asset owners can expect significant payback, reduced leaks, improved safety performance, and projects built or returned to service on schedule and within budget.
Hydratight pioneered the concept of treating the bolted joint as a weld, and has practised the essentials of this standard for more than 20 years. Hydratight has provided formally qualified and competent bolting craft personnel during this time, with all craft personnel undertaking classroom training, followed by practical workshops and examination before being permitted to work in the field on live projects.
Hydratight welcomes the publication of these updates to industry standards. Hydratight’s training and competency programs to ensure all bolting operations are carried out with an uncompromising approach to safety are mandatory for Hydratight’s craft personnel, and also available to customers and to the general market.
Joint integrity data management
Clearly defined procedures and acceptance quality standards supported by well-maintained data are crucial for assuring leak-free joints. Well thought out and proven software-based integrity management systems can provide a solution to mitigating risk on bolted flanges by providing traceability throughout joint life, going beyond leak prevention to actively improve safety by demanding competent work across the process.
Based on its own experience, Hydratight believes that true joint integrity management begins with a partnership between contractors and operators, which helps to significantly reduce leaks and improve the safety and integrity of all related assets.